Oh Sorry I didn't answer your question. I do think Wyandottes get too big for those 12x12 nest boxes. They have to cram their tail in the small square. At least my girl thought they were too small for her. HaHa.
I started with nine chicks; 1 light brahma which got really big; 1 Blue Wyandotte which got fairly big but not as big as the Brahma; 3 red sex links; two white leghorns; 1 white silkie. I had six 12x12 nest boxes and 2 24x24 nest boxes. they all sat atop a 15" shelf. None of the chickens would...
My boxes are 24x24. I have 4 lg boxes but they only use two of them. They like to pile in two chickens at a time. I have no idea why they seem to favor just those two boxes.
I have both larger nest boxes and the smaller ones. None of my birds would use the smaller boxes, so they now are storage. Wyandotte's are on the larger size so I would think the larger boxes would be best.
What are you feeding them? Are they getting enough protein. I hope they are not on layer feed if they are not laying. Do they have a safe coop so they are not stressed?
I don't think my Blue Wyandotte layed till 7 or 8 months old. She was the last of my chicks to start laying. But she has been consistent layer of small round tan eggs. I am a little disappointed the eggs are so small for such a big chicken. Also she goes broody a lot. Be prepared with a cage.